For example the patent publications FR-2287941 (corresponding to the publication U.S. Pat. No. 3991617) U.S. Pat. No. 4009611 and FI-57540 (corresponding to the publication U.S. Pat. No. 4151750) describe pipette tip removal mechanisms. They comprise a removal sleeve sliding on the cylinder part of the pipette and an arm fixed thereto and sliding in the handle of the pipette or on its side. The mechanism is also connected with a spring, which pushes the arm into the upper position. When the arm is pressed downwards, the sleeve loosens the tip fixed to the end of the cylinder.
A disadvantage of the known tip removal mechanisms is the fact that the force needed for the removal of the tip may be quite high, especially in multiple channel pipettes.